A suspension bridge normally consists of two towers that are mounted on opposite sides of a river bank, gorge, or the like, a main catenary cable spanned between them, and some sort of roadway or path suspended from the catenary cable. Such constructions can be huge engineering projects supporting several levels of multilane highway, or can be army or emergency-type structures that are erected on a temporary basis for relatively light traffic.
U.S. Pat. No. 411,499 of W. H. C. Greer of Sept. 24, 1889 describes what was for its day a heavy-duty suspension bridge. It was equipped with vertical suspenders, the elements by means of which the roadway or path is suspended from the main catenary cable, that could be shortened and lengthened to compensate for shifting of the towers or surrounding structure. Thus the bridge was adjustable.
In suspension bridges there is normally a tradeoff between ease of construction and safety of use. Thus light-duty suspension bridges erected for temporary military or emergency use which are simple enough to be erected by unskilled personnel can normally only be safely used by trained soldiers or mountaineers. Those that are so complex that they can only be erected by bridge engineers can normally be safely used by even the aged and infirm. Both types normally require extensive preparation at least, with complex preparation of anchors for the critical ends of the main cable and construction of tall support towers.